avfilter: add despill filter

Signed-off-by: Paul B Mahol <onemda@gmail.com>

Changelog

@@ -42,6 +42,7 @@ version <next>:
 - FITS muxer and encoder
 - add --disable-autodetect build switch
 - drop deprecated qtkit input device (use avfoundation instead)
+- despill video filter
 
 version 3.3:
 - CrystalHD decoder moved to new decode API

doc/filters.texi

@@ -6811,6 +6811,41 @@ FFmpeg was configured with @code{--enable-opencl}. Default value is 0.
 
 @end table
 
+@section despill
+
+Remove unwanted contamination of foreground colors, caused by reflected color of
+greenscreen or bluescreen.
+
+This filter accepts the following options:
+
+@table @option
+@item type
+Set what type of despill to use.
+
+@item mix
+Set how spillmap will be generated.
+
+@item expand
+Set how much to get rid of still remaining spill.
+
+@item red
+Controls ammount of red in spill area.
+
+@item green
+Controls ammount of green in spill area.
+Should be -1 for greenscreen.
+
+@item blue
+Controls ammount of blue in spill area.
+Should be -1 for bluescreen.
+
+@item brightness
+Controls brightness of spill area, preserving colors.
+
+@item alpha
+Modify alpha from generated spillmap.
+@end table
+
 @section detelecine
 
 Apply an exact inverse of the telecine operation. It requires a predefined

libavfilter/Makefile

@@ -166,6 +166,7 @@ OBJS-$(CONFIG_DEINTERLACE_VAAPI_FILTER)      += vf_deinterlace_vaapi.o
 OBJS-$(CONFIG_DEJUDDER_FILTER)               += vf_dejudder.o
 OBJS-$(CONFIG_DELOGO_FILTER)                 += vf_delogo.o
 OBJS-$(CONFIG_DESHAKE_FILTER)                += vf_deshake.o
+OBJS-$(CONFIG_DESPILL_FILTER)                += vf_despill.o
 OBJS-$(CONFIG_DETELECINE_FILTER)             += vf_detelecine.o
 OBJS-$(CONFIG_DILATION_FILTER)               += vf_neighbor.o
 OBJS-$(CONFIG_DISPLACE_FILTER)               += vf_displace.o framesync2.o

libavfilter/allfilters.c

@@ -178,6 +178,7 @@ static void register_all(void)
     REGISTER_FILTER(DEJUDDER,       dejudder,       vf);
     REGISTER_FILTER(DELOGO,         delogo,         vf);
     REGISTER_FILTER(DESHAKE,        deshake,        vf);
+    REGISTER_FILTER(DESPILL,        despill,        vf);
     REGISTER_FILTER(DETELECINE,     detelecine,     vf);
     REGISTER_FILTER(DILATION,       dilation,       vf);
     REGISTER_FILTER(DISPLACE,       displace,       vf);

libavfilter/version.h

@@ -30,7 +30,7 @@
 #include "libavutil/version.h"
 
 #define LIBAVFILTER_VERSION_MAJOR   6
-#define LIBAVFILTER_VERSION_MINOR 101
+#define LIBAVFILTER_VERSION_MINOR 102
 #define LIBAVFILTER_VERSION_MICRO 100
 
 #define LIBAVFILTER_VERSION_INT AV_VERSION_INT(LIBAVFILTER_VERSION_MAJOR, \

libavfilter/vf_despill.c

@@ -0,0 +1,183 @@
+/*
+ * Copyright (c) 2017 Paul B Mahol
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/opt.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+typedef struct DespillContext {
+    const AVClass *class;
+
+    int co[4]; /* color offsets rgba */
+
+    int alpha;
+    int type;
+    float spillmix;
+    float spillexpand;
+    float redscale;
+    float greenscale;
+    float bluescale;
+    float brightness;
+} DespillContext;
+
+static int do_despill_slice(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs)
+{
+    DespillContext *s = ctx->priv;
+    AVFrame *frame = arg;
+    const int ro = s->co[0], go = s->co[1], bo = s->co[2], ao = s->co[3];
+    const int slice_start = (frame->height * jobnr) / nb_jobs;
+    const int slice_end = (frame->height * (jobnr + 1)) / nb_jobs;
+    const float brightness = s->brightness;
+    const float redscale = s->redscale;
+    const float greenscale = s->greenscale;
+    const float bluescale = s->bluescale;
+    const float spillmix = s->spillmix;
+    const float factor = (1.f - spillmix) * (1.f - s->spillexpand);
+    float red, green, blue;
+    int x, y;
+
+    for (y = slice_start; y < slice_end; y++) {
+        uint8_t *dst = frame->data[0] + y * frame->linesize[0];
+
+        for (x = 0; x < frame->width; x++) {
+            float spillmap;
+
+            red   = dst[x * 4 + ro] / 255.f;
+            green = dst[x * 4 + go] / 255.f;
+            blue  = dst[x * 4 + bo] / 255.f;
+
+            if (s->type) {
+                spillmap = FFMAX(blue  - (red * spillmix + green * factor), 0.f);
+            } else {
+                spillmap = FFMAX(green - (red * spillmix + blue  * factor), 0.f);
+            }
+
+            red   = FFMAX(red   + spillmap * redscale   + brightness * spillmap, 0.f);
+            green = FFMAX(green + spillmap * greenscale + brightness * spillmap, 0.f);
+            blue  = FFMAX(blue  + spillmap * bluescale  + brightness * spillmap, 0.f);
+
+            dst[x * 4 + ro] = av_clip_uint8(red   * 255);
+            dst[x * 4 + go] = av_clip_uint8(green * 255);
+            dst[x * 4 + bo] = av_clip_uint8(blue  * 255);
+            if (s->alpha) {
+                spillmap = 1.f - spillmap;
+                dst[x * 4 + ao] = av_clip_uint8(spillmap * 255);
+            }
+        }
+    }
+
+    return 0;
+}
+
+static int filter_frame(AVFilterLink *link, AVFrame *frame)
+{
+    AVFilterContext *ctx = link->dst;
+    int ret;
+
+    if (ret = av_frame_make_writable(frame))
+        return ret;
+
+    if (ret = ctx->internal->execute(ctx, do_despill_slice, frame, NULL, FFMIN(frame->height, ff_filter_get_nb_threads(ctx))))
+        return ret;
+
+    return ff_filter_frame(ctx->outputs[0], frame);
+}
+
+static av_cold int config_output(AVFilterLink *outlink)
+{
+    AVFilterContext *ctx = outlink->src;
+    DespillContext *s = ctx->priv;
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(outlink->format);
+    int i;
+
+    for (i = 0; i < 4; ++i)
+        s->co[i] = desc->comp[i].offset;
+
+    return 0;
+}
+
+static av_cold int query_formats(AVFilterContext *ctx)
+{
+    static const enum AVPixelFormat pixel_fmts[] = {
+        AV_PIX_FMT_ARGB,
+        AV_PIX_FMT_RGBA,
+        AV_PIX_FMT_ABGR,
+        AV_PIX_FMT_BGRA,
+        AV_PIX_FMT_NONE
+    };
+    AVFilterFormats *formats = NULL;
+
+    formats = ff_make_format_list(pixel_fmts);
+    if (!formats)
+        return AVERROR(ENOMEM);
+
+    return ff_set_common_formats(ctx, formats);
+}
+
+static const AVFilterPad despill_inputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .filter_frame = filter_frame,
+    },
+    { NULL }
+};
+
+static const AVFilterPad despill_outputs[] = {
+    {
+        .name         = "default",
+        .type         = AVMEDIA_TYPE_VIDEO,
+        .config_props = config_output,
+    },
+    { NULL }
+};
+
+#define OFFSET(x) offsetof(DespillContext, x)
+#define FLAGS AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_VIDEO_PARAM
+
+static const AVOption despill_options[] = {
+    { "type",       "set the screen type",     OFFSET(type),        AV_OPT_TYPE_INT,     {.i64=0},     0,   1, FLAGS, "type" },
+    {   "green",    "greenscreen",             0,                   AV_OPT_TYPE_CONST,   {.i64=0},     0,   0, FLAGS, "type" },
+    {   "blue",     "bluescreen",              0,                   AV_OPT_TYPE_CONST,   {.i64=1},     0,   0, FLAGS, "type" },
+    { "mix",        "set the spillmap mix",    OFFSET(spillmix),    AV_OPT_TYPE_FLOAT,   {.dbl=0.5},   0,   1, FLAGS },
+    { "expand",     "set the spillmap expand", OFFSET(spillexpand), AV_OPT_TYPE_FLOAT,   {.dbl=0},     0,   1, FLAGS },
+    { "red",        "set red scale",           OFFSET(bluescale),   AV_OPT_TYPE_FLOAT,   {.dbl=0},  -100, 100, FLAGS },
+    { "green",      "set green scale",         OFFSET(greenscale),  AV_OPT_TYPE_FLOAT,   {.dbl=-1}, -100, 100, FLAGS },
+    { "blue",       "set blue scale",          OFFSET(bluescale),   AV_OPT_TYPE_FLOAT,   {.dbl=0},  -100, 100, FLAGS },
+    { "brightness", "set brightness",          OFFSET(brightness),  AV_OPT_TYPE_FLOAT,   {.dbl=0},   -10,  10, FLAGS },
+    { "alpha",      "change alpha component",  OFFSET(alpha),       AV_OPT_TYPE_BOOL,    {.i64=0},     0,   1, FLAGS },
+    { NULL }
+};
+
+AVFILTER_DEFINE_CLASS(despill);
+
+AVFilter ff_vf_despill = {
+    .name          = "despill",
+    .description   = NULL_IF_CONFIG_SMALL("Despill video."),
+    .priv_size     = sizeof(DespillContext),
+    .priv_class    = &despill_class,
+    .query_formats = query_formats,
+    .inputs        = despill_inputs,
+    .outputs       = despill_outputs,
+    .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | AVFILTER_FLAG_SLICE_THREADS,
+};